Oil-filled insulating bushing



Jan. 13, 1931. G. E. JANssoN OIL FILLED INSULATING. BUSHING Filed June 30, 1926 y Patentedv Jan. 13, 1931 Unire s'rArEs PATENT* OFFICE GUsrAv JANsson, orl wonnnsron, MASSACHUSETTS Assrenoa rro connrr Etno- '.rnoAr. raAnUrAorUnrne oonronA'rion, or SOUTH BosaoN, MASSACHUSETTS, A

ooRPonATo'N on` MASSACHUSETTS OIL-FILLED iNsULA'rrNG RUSHINGl Application filed `June 30,

his invention relates to electric insulators and particularly to oil lilled insulators of the bushing typewhich have an outer casing comprising a plurality of insulating sections. l

Various methods have been proposed to prevent the escape of oil through the joint between the insulating sections. A cemented oint is desirable because oit its simplicity and cheapness, but has the disadvantage that iiuid, and especially oil,'niay,` under certain conditions, slowlyseep through the cement. Any loss of oil in a bushing otthis type is attended by a `corresponding weakening oi the vinsulating properties of the bushing hence a perfectly tight joint is a necessity.

lt is an object of this invention to provide a construction in conjunction with acemented joint of an insulating bushing which will provide a fluid-tight joint thereat.

It is a further object to provide fluid sealing meansV for a cemented joint between two porcelain sections of a bushing of this type which can be readily inspected and repaired without dismantling the insulator.

A still further object is generally to improve the construction of oilfilled insulating bushings.` i

Certain features hereinillustrated and described are claimed in my co-pending `application Serial No. 119,724 filed June 30, 1926.

Fig. 1 is an elevation partly in section of an insulator embodying the invention.

Fig. 2 is an enlarged sectional detail of the` insulator of Fig. 1in the vicinity of the attaching sleeve.

Fig. 8 is a plan view of the attaching sleeve.

As here shown, the insulating bushingV 192e. serial No'. 119,723.

tures 28 of the metal cylinder 20. Said reservoir cover 24 is provided with an axial opening through which a conductor or stud 32 is adapted to pass freely and said opening 1s covered against entrance of water by a cover 34 wluchis screw-threaded on said conductor andwhich has a depending apronV 36 which surrounds said'opening.

The lowerinsulating section 141s provided with an opening 1n its lower end 1n `which a bushing 38 is secured by means of body of cement 40. Said conducting stud 82 is adapted to be screw-threaded through and extended beyond said bushing andaloclnutj41r screwedonto tie lower extended end of said conductor to hold saidstud 'against rotation. Apaclring 42 is disposed between Lsaid nut and the bottom oi' the insulator to provide an oil tight seal thereat. Said metal` collar 18' is provided withan integral OutStandingliange 44 by which the bushing `is adapted to be secured to the casing 46 of any suitable electrical apparatus. The internal diameter of said collar is adapted' to be slightly larger than the diameter of the insulating sections 10fand 14 to provide `an annular space therebetween to receive a body of cement 47 by which said upper4 and lower insulating sections are permanently and rigidly affixed to said attaching sleeve 18. Annular grooves 48 are provided on the inner surface of said sleeve into which the cement may'enter, thus enhancing the strength of the joint. The inner edges of'said sleeve 18 `are bevelled at the topv and bottom to provide the peripheral angular faces 50 which are preferably at an angle of about 45 with the side walls of the insulating sections 10 and 14.

As hasbeen previously set forth, it has been cof found that cement cannot be depended upon for a completely `fluid tight joint under certain conditions en account of its porous strucn ture and this is particular y true in the case of a fluid which has the penetrating qualities of oil. Consequently, means are provided to maintain an oil tight oint between the sleeve and the insulating sections l and le at the ends of the cement body. At the top et said sleeve said means preferably comprises an annular yieldii'ig` packing substantially triangular' in section, which is adapted to encircle the upper insulating section, above the mass 01"' cement 47 and to lit within the angular groove formed by said faces 5() andthe insulating section 10. Said sleeve is provided with an outstanding annular flange 54 at its upper edge and bolts 55 passing through said flange are screw-threaded into a clamping ring 56 disposed above said flange and said packing. Said clamping ring is provided with an annular projection, or ridge, 58 which is arranged to bear against said packing 52 and to press it iirmly against the vangularly related aces of said sleeve and said insulating section l0, thereby providing a fluid-tight seal above the cement. A fluid tight joint is provided at the bottom ot said. sleevel in a similar manner by the packing 60 and a clamping ring 62, which secured to the sleeve by screw-threaded bolts 63.

This construction has the advantage that the fluid tight seal is not a part of the inechanical structure of the bushing and is readily accessible without dismantling the insulator in case it is desirable to renew the packing. The lower cape oi said upper insulat ing section l0 may be provided with a metallic lining G5 in the vicinity or' the metal sleeve 18 which lining is closely adherent to the surtace and is conformed with the surface-irregularities of the bushing and said lining may be extended below said cape to a point where it will be connected electrically with the clamping ring 56 and consequently with the casing 46. The effect of this metal lining is to prevent a concentration of the iux at the top of the sleeve 18 and thus lessen the liability of breakdown this point. may be constructed of thin sheet metal as metal foil, or may be spray deposited or otherwise.

rlhe construction may be modified without departing 'from the scope of the invention.

I claim:

l. An oil filled insulating bushing including an insulating conductor-enclosing shell, a metal supporting sleeve currounding and connected with said shell, external sealing means for the joint between said sleeve and shell including a packing ring disposed at the end of said sleeve between it and said shell, a clamping ring carried by said sleeve arranged to bear against said. packing ring,

The liningl incense and a thin metal coating mechanically independent o'f said sleeve carried by said shell at and extended above said sealing means arranged in strong mechanical adherency and in intimate contact with and conformed with the surface irregularities oic said tube and having an electrical connection with said clamping' ring.

2. An oiltilled insulating bushing including an outer oil-containing insulating shell comprising a pair ci juxtaposed insulating tubes, a metal collar disposed about the confronting ends of said tubes and spaced from at least one ot them, a body of cement in the space between said collar and tube, the oil within said shell having` access to the cement, sealing means located in said space above the cement and arranged to seal the space against escape of oil passing through and around said body of cement, means including a metal clamping ring connected with said collar and bearing on said packing means, and an electrostatic shield c rried by said insulating shell and located between it and said clamping` ring, and connected electrically with said collar.

ln testimony whereof, l have signed my naine to this specilication.

GUSTAV E. JANSSON. 

